What is the ruling on a woman uncovering her head before the husband of her sister or the husband of her paternal or maternal aunt? What is the ruling on travelling with them as Mahrams (permanently unmarriageable) for ‘Umrah, Hajj and so on?

All perfect praise be to Allaah, the Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

A man's being a husband of a woman's sister or paternal or maternal aunt does not render him a Mahram for her. Therefore, it is impermissible for a woman to uncover her hair before these men, travel with them as Mahrams or do anything else that is only permissible to do with Mahram men.

Allaah Knows best.